The demand for microprocessors to be made smaller is ever present because size reduction typically increases speed and decreases power consumption. Generally, making microprocessors smaller entails making the components of the microprocessors smaller. Transistors are one of the basic components of microprocessors. Thus, reducing the size of transistors enables microprocessors to be made smaller and, hence, have increased performance.
Transistors are typically manufactured by forming layers of material on top of one another with some type of processing being performed on each layer before depositing the next layer. Because some of the steps in the processing affect the entire device, at some stages of manufacturing, portions of the transistors must have inhibiting materials applied in order to at least retard the effects of certain later manufacturing steps. These inhibiting materials may often be applied to only inhibit the effects of a particular manufacturing step and, thus, may be of limited usefulness after they have served this purpose.
Unfortunately, once these limited purpose inhibiting materials have served their purpose, they may be difficult to remove. For example, since the components of transistors are typically quite small, on the order of a few to a few hundred nanometers—10−9 meters, reducing the size of these materials by machining techniques is quite difficult, if not impossible. Moreover, because transistors are typically composed of a variety of materials, the application of an etchant to reduce the size of a particular material is problematic because the etchant tends to dissolve materials that do not require reduction.